Motion conversion mechanism



June 4, 1968 G. N; w|| |s 3,386,297

MOTION CONVERSION MECHANISM Filed May 23, 1966 mu A W WI T .8; l ll i! W WIMIVAI 34 41mm"! Z4 Z4 ffG-z g5 INVENTOR. GRANT N. WILLIS BYW,

ATTORNEYS United States Patent Office 3,3862%}? Fatented June 4, 1968 3,386,297 MOTION CONVERSION MECHANISM Grant N. Willis, Bristol, Conn, assignor to The Arthur G. Russell Company, Incorporated, Bristol, Conn, a t

corporation of Connecticut Filed May 23, 1966., Ser. No. 551,997 9 Claims. (Cl. 74-99) ABSTRACT OF THE DlISCLOSURE This invention generally relates to motion conversion mechanisms and particularly concerns a mechanism usalble, e.g., with automatic feeding equipment in handling articles.

A principal object of the invention is to provide an improved motion conversion mechanism particularly suited for high speed handling of small parts such as miniaturized electronic components that are difficult to handle.

Another object of the invention is to provide an improved mechanism Which may be incorporated in both new and existing article handling equipment and which is useful in manipulaitng parts of varying size and shape in a high speed production operation.

A further object of the invention is to provide an improved mechanism of the above described type which is of compact construction having a minimum number of parts and which is fast and durable in operation for use over extended periods of time.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth, and the scope of the application which will be indicated in the appended claims.

In the drawing:

FIG. 1 is a front elevational view, partly in section and partly broken away, showing a preferred embodiment of a motion conversion mechanism constructed in accordance with this invention;

FIG. 2 is a side elevational view, partly in section and partly broken away, showing the mechanism of FIG. 1 on a reduced scale; and

FIG. 3 is a section view, partly broken away, taken generally along line 3-3 of FIG. 1.

Referring now to the drawing in detail, a motion conversion mechanism is shown including a housing 12 having an upper base member 14 and a lower body member 16, the base and body members 14, 16 preferably being rectangular in shape and releasably secured by bolts such as at 18.

A pair of levers 20 are supported on the lower body member 16 for pivotal movement in a bottom slot 22 defined by a pair of ribs 24. Each lever 20 is of L-shape having perpendicular integral arm portions 26 and 28. Arm portions 26 are each secured, adjacent the juncture with their respective arm portions 28, by pivot pins supported by the ribs 24 such that the levers 20 are spaced opposed with their arm portions 26 projecting in opposite directions in slot 22. Arm portions 28 are positioned adjacent one another and project downwardly from the lower body member 16 of the housing 12.

In the use of the mechanism 10, the housing 12 is mounted on a supporting structure such as that of a power operated transfer unit of an automatic feeding system, e. g., which is not a part of this invention and is not illustrated. The arm portions 28 are desirably provided with threaded holes as at 31 whereby special fingers, not shown, may be attached for handling a workpiece.

Referring now more particularly to the housing 12, centrally disposed coaxial passageways 32 and 34 are formed in the base and body members 14 and 16. The lower end of passage-way 32 and the upper end of passageway 34 are respectively provided with shallow cylindrical chambers 36, 38 positioned in oppositely facing relation and forming an operating cylinder 40 within housing 12. The lower end of the passageway 32 is enlarged to provide a radial shoulder 42 which assists in fixing a bushing 44 against axial movement upon insertion of the bushing 44 in the passageway 32.

To operate the levers 20, a drive member or actuator 46 is centrally mounted in the housing 12 and is shown supported by a diaphragm 48 fixed between the base and body members 14, 16 to extend transversely across the operating cylinder 40 for flexural movement therein in opposite axial directions. The diaphragm 48 is formed preferably of urethane rubber or other durable resilient material.

A pair of disks 50 and 52 are provided at the head of the actuaotr 46 on opposite sides of the diaphragm 48, and a rod 54 extends downwardly from the lower disk 52 through the passageway 34 of the lower body member 16. The disks 50 and 52 each have a diameter slightly less than that of the operating cylinder 40 and are retained in axial alignment with the rod 54 by a screw, not shown, maintaining the actuator 46 in assembled relation as a single unit supported by the diaphragm 48.

To provide a low friction driving connection between the unitary actuator 46 and the levers 20 which will be highly responsive to flexural movements of the diaphragm 48, a reduced end portion 56 of rod 54 is provided with a radial end flange 58 held captive by opposing knife edge portions 60 and 62 on an inside edge surface 64 of each lever 20. The knife edge portions 60, 62 are formed by a pair of apertures 66 which extend parallel to the pivot axes of the levers 20 and provide oppositely facing slots across their inside edge surfaces 64. The slots are suitably dimensioned to receive the radial end flange 58 whereby the knife edge portions 60, 62 provide line contact engagement with the opposite surfaces of the radial end flange 58 and effect a low friction driving connection. The radial end flange 58 extends into the apertures 66 with sufficient clearance to permit a limited reciprocating movement of the rod 54 without binding or interfering with the levers 20. The levers 20 are shown with their inside edge surfaces 64 closely spaced opposed to one another and having their upper portions relieved at 67 to accommodate the reduced end portion 56 of rod 54 which projects downwardly between the levers 20 from the body member 16.

The housing 12 includes passages 68 and 70 respectively formed in the base and body members 14 and 16 for cornmunicating with the upper and lower chambers 36, 38- of the operating cylinder 40. Passages 68, 79 both extend radially outwardly from the operating cylinder 40 in the same direction. Such an arrangement permits either passage 68 or 70 to be conveniently connected in a well known manner to a source of Pressurized fluid such as compressed air.

In the operation of the specific illustrated embodiment, compressed air is introduced through passage 63 into the upper chamber 35 of the operating cylinder it to cause the diaphragm 48 to be thrust downwardly, forcing air under the diaphragm 48 to vent from the lower chamber 38 to atmosphere through the passage 70 as the rod 5 of the actuator 46 forces the levers 2a to pivot into an open position. Upon release of the air pressure in the upper chamber 36, the diaphragm 48 will flex upwardly into the position shown in the drawing under the biasing force of a pair of compression or return springs 72 to pivot the levers 29 into their illustrated closed position and condition the mechanism for a repeat operation. The return springs 72 are seated in compartments 74 formed in body member 16 and extend axially of rod 54 into engagement with the lower disk 52 of the actuator 46.

To handle workpieces of varying size and shape, the mechanism 10 is provided with adjustable stops for selec tively limiting the pivotal movement of the levers 2% in opposite angular directions. For this reason, the outer extremities of the arm portions 26 are shown having threaded bores 76 for receiving stop screw 78. The stop screws 78 are engageable with a pair of steel balls 80 staked to the bottom of the body member 16 intermediate the ribs 24 whereby the extent of lever movement in an opening direction may be selectively limited by adjusting the screws 78. The closed position of the levers 26 is adjusted by a stop screw 82 threadably mounted in the opening through the bushing 44 to extend into the upper chamber 36 of the operating cylinder 40 and engage the upper disk 50 of the actuator 46, positively stopping the pivotal movement of the levers toward one another.

To ensure a mechanism 10 of maximum versatility, the base portion 14 of the housing 12 is also provided with compartments 84, similar in structure and function to the above-described compartments 74, such that the separable base and body members 14, 16 of the housing 12 may be disassembled to reverse the position of the return springs 72 relative to the diaphragm 43. Upon reassembly, the pickup device 10 will be adapted for applications wherein the levers 20 are normally open as distinguished from their normally closed condition in the illustrated embodiment. Accordingly, compressed air would then be introduced through passage 70 into the lower chamber 38 of the operating cylinder 40 in opposition to the biasing force of the return springs 72 to cause the actuator 46 to be thrust upwardly to close the levers 2t}, and the air in the upper chamber will be vented to atmosphere through passage 68. To prevent leakage of compressed air from the lower chamber of the operating cylinder 48 through the bore 34, rod 54 is shown having a necked-down intermediate segments 86 with a surrounding O-ring 88 engaging the wall of the passageway 34 for sealing oh the operating cylinder 40 from atmosphere.

It is to be noted that in addition to providing the necessary force for returning the actuator 46, the return springs 72 may be preselected to provide a cushioning effect to counter-balance the driving force of a predetermined operating air pressure. A workpiece may be grasped, e.g., either externally or internally depending on whether the levers 20 are adapted for normally open or normally closed applications, and the force effected by the levers 20 will be acceptable for the intended purpose despite a high speed of operation.

By virtue of the above-described structure, a motion conversion mechanism of maximum utility is provided in a compact durable unit incorporating a minimum number of parts. Moreover, the described mechanism is highly responsive to actuation so as to be capable of completing a large number of accurate operations in a short period of time. In addition to being of notable use in a variety of high speed production operations, the described invention is particularly suited for transferring small parts that are normally diflicult to handle.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure abovedescribed will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

I claim:

1. A motion conversion mechanism comprising a housing, a pair of opposed cooperating levers supported on said housing for pivotal movement toward and away from one another, said levers each being contoured to provide a pair of spaced opposed knife edge portions, and a reciprocable center drive member mounted in said housing and positioned between said levers, said center drive member being connected to each of said levers intermediate their pivot axes and being held captive between said knife edge portions on each of said levers in line contact engagement therewith for providing a low friction drive for pivoting said levers toward and away from one another.

2. The mechanism of claim 1 wherein said housing includes an operating cylinder and a passageway extending axially therefrom, and a resilient diaphragm mounted in said housing and extending transversely across said operating cylinder for flexural movement therein, and wherein said center drive member is suported by said diaphragm for reciprocable movement in said passageway in response to flexural movement of said diaphragm for operating said levers.

3. The mechanism of claim 2 further including adjustable stops for selectively limiting the extent of pivotal movement of said levers toward and away from one another.

4. The mechanism of claim 2 wherein said diaphragm divides said operating cylinder into first and second chambers, and wherein said housing includes a supply and exhaust passage formed therein in communication wiith said first chamber for selectively supplying fluid to and exhausting it from the same "for controlling flexural movement of said diaphragm in said operating cylinder.

5. The mechanism of claim 2 wherein said housing includes separable base and body portions each having a cylindrical compartment therein disposed in oppositely facing relation and defining said operating cylinder, said diaphragm being mounted between said base and body portions and dividing said operating cylinder into first and second chambers, and wherein a fluid passage is formed in each of said base and body portions in communication with its respective cylindrical compartment for supplying fluid to and exhausting it from said first and second chambers of said operating cylinder alternatively.

6. The mechanism of claim 4 further including a spring received in said second chamber for continuously exerting a spring force on said diaphragm in opposition to the force of fluid pressure acting thereon in said first chamber.

7. The mechanism of claim 5 further including a spring received in one of said first and second ch ambers for continuously exerting a spring force on said diaphragm in opposition to the force of fluid pressure acting thereon in the other of said first and second chambers.

8. A motion conversion mechanism comprising a housing, a pair of opposed cooperating levers supported on said housing for pivotal movement toward and away from one another, and a reciprocable center drive member mounted in said housing and positioned between said levers, said center drive member being connected to each of said levers intermediate their pivot aXes for operating said levers, said levers each being L-shaped and having first and second arm portions, said first arm portions projecting outwardly of said housing for cooperative action, and said second arm portions each having a stop mounted thereon and engageable with said housing, each said stop being adjustable for selectively limiting the extent of pivotal movement of its respective lever away from the other of said levers.

9. A motion conversion mechanism comprising a housing, a pair of opposed cooperating levers each having a pivot pin secured to the housing and providing a fixed pivot axis for supporting said levers on said housing for pivotal movement toward and away from one another 5 about fixed centers, and a reciprocable center drive member mounted in said housing and positioned between said levers, said center drive member being connected to each of said levers intermediate their pivot axes for operating said levers.

References Cited UNITED STATES PATENTS 361,162 4/1887 Jacobs 74 79 2,103,214 12/1937 Coffin 92 13 XR 2,492,465 12/1949 Dahl 92 100 XR FRED C. MATTERN, 1a., Primary Examiner.

F. D. SHOE-MAKER, Assistant Examiner.

Disclaimer 3,386,297.Gmnt 1V. Willis, Bristol, Conn. MOTION CONVERSION MECHANISM. Patent dated June 4, 1968. Disclaimer filed Nov. 13, 1972, by the assignee, The Arthur G. Russell Company, Incorporated. Hereby enters this disclaimer to claim 9 of said patent.

[Ofioial Gazette Febmary 19,1974] 

